1 files changed, 95 insertions, 0 deletions
diff --git a/src/main/java/com/zaxxer/hikari/metrics/PoolStats.java b/src/main/java/com/zaxxer/hikari/metrics/PoolStats.java
new file mode 100644
index 0000000..e8905d1
--- /dev/null
+++ b/src/main/java/com/zaxxer/hikari/metrics/PoolStats.java
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2015 Brett Wooldridge
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.zaxxer.hikari.metrics;
+
+import static com.zaxxer.hikari.util.ClockSource.currentTime;
+import static com.zaxxer.hikari.util.ClockSource.plusMillis;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ *
+ * @author Brett Wooldridge
+ */
+public abstract class PoolStats
+{
+   private final AtomicLong reloadAt;
+   private final long timeoutMs;
+
+   protected volatile int totalConnections;
+   protected volatile int idleConnections;
+   protected volatile int activeConnections;
+   protected volatile int pendingThreads;
+
+   public PoolStats(final long timeoutMs)
+   {
+      this.timeoutMs = timeoutMs;
+      this.reloadAt = new AtomicLong();
+   }
+   
+   public int getTotalConnections()
+   {
+      if (shouldLoad()) {
+         update();
+      }
+
+      return totalConnections;
+   }
+
+   public int getIdleConnections()
+   {
+      if (shouldLoad()) {
+         update();
+      }
+
+      return idleConnections;
+   }
+
+   public int getActiveConnections()
+   {
+      if (shouldLoad()) {
+         update();
+      }
+
+      return activeConnections;
+   }
+
+   public int getPendingThreads()
+   {
+      if (shouldLoad()) {
+         update();
+      }
+
+      return pendingThreads;
+   }
+
+   protected abstract void update();
+
+   private boolean shouldLoad()
+   {
+      for (; ; ) {
+          final long now = currentTime();
+          final long reloadTime = reloadAt.get();
+          if (reloadTime > now) {
+              return false;
+          }
+          else if (reloadAt.compareAndSet(reloadTime, plusMillis(now, timeoutMs))) {
+              return true;
+          }
+      }
+  }
+}